[bn_breen]

I just recently acquired a 00' z3 m roadster. When I got it I noticed it had a cheap DUAL head unit and there was speaker wire wrapped around the seats. Upon further inspection I found everything to be wired up right but I do not have any sound at all. I tore everything down today trunk carpet and rear deck carpet and started tracing wire still have not found any problem. I suspect I have a bad amp (which is $200 to replace).

SO FOR THE ADVICE

I've been thinking that I could remove the amp wiring and run the speakers directly to the head unit (which I would replace as well). With the money I would save from not replacing the amp I would be able to replace all my interior speakers and be able to run an aftermarket amp later on that would by far produce better sound than the stock z3 system. I was going to remove the middle speaker from the back, keep the two rears, floor, and door speakers. Any advice before I undergo this project would be greatly appreciated.
Thank you in advance!!!

Just thought of another question since I am pretty sure i'm going to do this. Where should I run the 12v constant and switched wires to or should I just keep those wires original?

 

[Blacklane]

There is no reason your plan won't work. It looks like you're retaining the only good components of the stereo: the wires.

The electrons don't really care if the amplifier is in the head unit or the trunk, but trunk-mounted amplifiers can be much larger and more powerful. The HK system is claimed to be 6 channels at 25W each plus 2 channels at 40W. But that's with an outrageous 10% total harmonic distortion. Realistically, it's about half that. If you can find a head unit that is comparable, it should work OK. 80W X2 channels might be sufficient. A little more would be better (remember this is an open roadster).

The head unit will only have full-range outputs (left & right), so you can't connect that to the door tweeters. You will either have to use only the footwell speakers, install crossovers in the trunk, or add bass-blockers to the tweeter lines. More than likely the door tweeters are shot anyway. If you use component speakers, you can glue the new tweetes in the door from the inside.

You might want to consider at least adding a mono amp in the trunk to drive the subwoofer. 100 watts is about right for that subwoofer, and that's a lot to expect from a head unit amp. A 200 W amp at half gain will perform better.